S.F. quake report: City must rebound quickly

Robert Selna, Chronicle Staff Writer

Published
4:00 am PST, Monday, February 2, 2009

Alex Martinez levels a beam at the EcoCenter construction site at Heron's Head Park in San Francisco, Calif., on Thursday, Jan. 15, 2009. Construction of the environmentally-conscious interpretive center, slated to open in April, may be stalled because of the ongoing state budget crisis. less

Alex Martinez levels a beam at the EcoCenter construction site at Heron's Head Park in San Francisco, Calif., on Thursday, Jan. 15, 2009. Construction of the environmentally-conscious interpretive center, ... more

Photo: Paul Chinn, The Chronicle

Photo: Paul Chinn, The Chronicle

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Alex Martinez levels a beam at the EcoCenter construction site at Heron's Head Park in San Francisco, Calif., on Thursday, Jan. 15, 2009. Construction of the environmentally-conscious interpretive center, slated to open in April, may be stalled because of the ongoing state budget crisis. less

Alex Martinez levels a beam at the EcoCenter construction site at Heron's Head Park in San Francisco, Calif., on Thursday, Jan. 15, 2009. Construction of the environmentally-conscious interpretive center, ... more

Photo: Paul Chinn, The Chronicle

S.F. quake report: City must rebound quickly

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San Francisco's buildings and infrastructure are fundamentally unprepared to handle the big earthquake that will surely hit the city sometime in the coming decades, according to a report by a leading local public policy think tank.

The report, scheduled for release Tuesday by the San Francisco Planning & Urban Research Association, or SPUR, was two years in the making and examined a broad range of city earthquake preparedness issues - from building codes and retrofit guidelines to earthquake recovery timelines.

Some of the key findings seem surprisingly basic for a city that has such a long and storied history with earthquakes.

"We live in earthquake country, but we all try to put it out of our minds," said SPUR Executive Director Gabriel Metcalf. "Loma Prieta may have lulled us into a false sense of security because thousands of people did not die, but if we have a larger earthquake we are simply not prepared."

The report, which The Chronicle obtained Friday, notes that the city has more than 120,000 buildings and that at least 90 percent of them were erected before the adoption of modern building codes in the 1970s. Some 30,000 buildings could be damaged beyond repair in a Loma Prieta-like earthquake of 6.9 magnitude, the report said. Scientists expect the next big quake to be a magnitude of at least 7.2.

The report describes the bleak conditions the city will face if it does not do more to prepare before that quake occurs.

"The damage has cascading consequences for San Francisco," it said. "People are displaced from their homes ... reconstruction demands overwhelm the city's damaged infrastructure. Years later, San Francisco has failed to recover and is no longer seen as the center of the region."

The draft city study argues that San Francisco could avoid $1.5 billion in damage and the displacement of tens of thousands of residents if it forced owners of 2,800 of the weakest residential buildings - known as soft-story buildings - to retrofit.

The large, wood-frame structures make up only 10 percent of the residential units that are believed to be unsafe, but they are the most vulnerable to severe earthquakes.

Other dangerous building types and retrofit strategies will be studied by the city in the coming months, and future reports are expected. The studies are a first endeavor to understand the health, safety and economic risk posed by the city's buildings during a major earthquake.

A Chronicle report in June highlighted the city's lack of a strategy for fixing the soft-story problem despite the fact that the danger had been known for decades. At that time, Mayor Gavin Newsom said he did not feel it was necessary to require owners to shore up their buildings as other Bay Area cities have done. Last month, Newsom said he would be willing to reconsider after reviewing more data.

Newsom's spokesman, Joe Arellano, was not available on Friday to comment on the SPUR report.

The SPUR report takes a broader view than the earlier building department analysis, which relates specifically to the city's building stock.

"We wanted to step back and ask how to avoid becoming a New Orleans where we won't be able to recover," said Chris Poland, a structural engineer who led the SPUR study.

He said the most important conclusion in the SPUR study is that residential buildings need to withstand earthquakes to the extent that they can be inhabited within 24 hours of a big quake, and that neighborhoods need to be back to normal within 30 to 60 days.

"We learned from New Orleans that people had to leave the city," Poland said. "You have to be able to put people back in their homes so that they can get back to work and rebuild the city."